Abstract

BackgroundRotavirus, predominantly of group A, is a major cause of severe diarrhoea worldwide, withthe greatest burden falling on young children living in less-developed countries. Vaccinesdirected against this virus have shown promise in recent trials, and are undergoingeffectiveness evaluation in sub-Saharan Africa. In this region limited childhood data areavailable on the incidence and clinical characteristics of severe group A rotavirus disease.Advocacy for vaccine intervention and interpretation of effectiveness following implementationwill benefit from accurate base-line estimates of the incidence and severity of rotaviruspaediatric admissions in relevant populations. The study objective was to accurately define theincidence and severity of group A rotavirus disease in a resource-poor setting necessary tomake informed decisions on the need for vaccine prevention.Methods and FindingsBetween 2002 and 2004 we conducted prospective surveillance for group A rotavirusinfection at Kilifi District Hospital in coastal Kenya. Children < 13 y of age were eligible as"cases" if admitted with diarrhoea, and "controls" if admitted without diarrhoea. We calculatedthe incidence of hospital admission with group A rotavirus using data from a demographicsurveillance study of 220,000 people in Kilifi District. Of 15,347 childhood admissions 3,296(22%) had diarrhoea, 2,039 were tested for group A rotavirus antigen and, of these, 588 (29%)were positive. 372 (63%) rotavirus-positive cases were infants. Of 620 controls 19 (3.1%, 95%confidence interval [CI] 1.9–4.7) were rotavirus positive. The annual incidence (per 100,000children) of rotavirus-positive admissions was 1,431 (95% CI 1,275–1,600) in infants and 478(437–521) in under-5-y-olds, and highest proximal to the hospital. Compared to children withrotavirus-negative diarrhoea, rotavirus-positive cases were less likely to have coexistingillnesses and more likely to have acidosis (46% versus 17%) and severe electrolyte imbalanceexcept hyponatraemia. In-hospital case fatality was 2% among rotavirus-positive and 9%among rotavirus-negative children.ConclusionsIn Kilifi > 2% of children are admitted to hospital with group A rotavirus diarrhoea in the first5 y of life. This translates into over 28,000 vaccine-preventable hospitalisations per year acrossKenya, and is likely to be a considerable underestimate. Group A rotavirus diarrhoea isassociated with acute life-threatening metabolic derangement in otherwise healthy children.Although mortality is low in this clinical research setting this may not be generally true inAfrican hospitals lacking rapid and appropriate management.